Doctors have implanted a second patient with an experimental artificial heart.

Under a shroud of secrecy another French patient has received an artificial heart transplant from doctors working to perfect the pioneering procedure, just months after the world’s first recipient died.

The heart was implanted three weeks ago in a hospital in the eastern France city of Nantes, but was only reported until now.

“Apparently, everything went well but we know nothing about that patient,” French daily Libération said.

The newspaper added that it had not been able to get an official confirmation from the company Carmat, which made the heart.

The device is designed to replace the real heart for as long as five years, mimicking nature’s work using biological materials and sensors.

It aims to extend life for thousands of patients who die each year while awaiting a donor.

The company was temporarily forced to suspend clinical tests of its artificial heart in March, after the first patient implanted with one died two-and-a-half months after his operation.

Before he was fitted with the device, the man was suffering from terminal heart failure and was said to have only a few weeks, or even days, to live.

Carmat announced in July that it had been authorised to resume clinical tests.